The technical and economic indicators of the screening process are screening efficiency and productivity. The former is the quality indicator and the latter is the quantity indicator. There is a relationship between them, and it is also related to many other factors that determine the outcome of screening. The factors affecting the screening process can be roughly divided into three categories:

First, the physical properties of the material being sieved

It includes the particle size composition of the material itself, humidity, mud content and shape of the particles. When the fines content of the material is large, the productivity of the sieve is also large. When the humidity of the material is large, the screening efficiency generally decreases. However, the larger the mesh size is, the smaller the influence of water is. Therefore, for the wet material with large moisture content, in order to improve the screening process, it is generally possible to adopt a method of increasing the mesh hole or adopting wet screening. The material contains a large amount of mud (when the mud content is greater than 8%) should be wet screening, or pre-washed.

Second, the nature of the screen surface and its structural parameters

The vibrating screen makes the particles and the screen surface move vertically, so the screening efficiency is high and the production capacity is large. The relative movement of the particles and the screen surface is mainly a rod sieve, a plane vibrating screen, a cylinder sieve, etc. which are parallel movement, and the screening efficiency and productivity are low. For a given material, the productivity of the sieve and the efficiency of the screening are determined by the size of the mesh. Productivity depends on the width of the screen surface and the screen width is high. The screening efficiency depends on the length of the screen surface, and the screening length is high. Generally, the aspect ratio is 2, and the larger the effective sieve area (i.e., the ratio of the mesh area to the entire screen area), the higher the productivity per unit area and the screening efficiency. The larger the mesh size, the greater the productivity of the unit sieve surface and the higher the screening efficiency.

Third, the impact of production conditions

When the load of the sieve is large, the screening efficiency is low. To a large extent, the peace rate of the sieve depends on the size of the mesh and the overall screening efficiency; the larger the mesh, the lower the efficiency of the screening, the higher the productivity. Feed uniformity is of great significance to the screening process.